1. Field of the Invention
The present invention relates to a solid-state image capture device and an image capture apparatus.
2. Description of the Related Art
Typically, solid-state image capture devices have sensitivities to not only light in a visible-wavelength range (about 400 to 700 nm) but also to near infrared light having longer wavelengths. Thus, when the solid-state image capture devices are used for image capturing for cameras, images appear unnatural.
In order to avoid such an inconvenience, typically, a filter for eliminating light having longer wavelengths than visible light (the filter is hereinafter referred to as an “IR cut filter”) is disposed adjacent to a camera lens.
A sensitivity characteristic of such a solid-state image capture device is utilized and a bright image is generated in a situation in which the amount of incident light is small through use of near infrared light together with visible light without use of an IR cut filter. Thus, a system for mechanically creating states in the presence and absence of an IR cut filter in accordance with brightness have been proposed (e.g., refer to Japanese Unexamined Patent Application Publication Nos. 2000-59798, 2000-224469, 2004-337718, and 2005-45559).
However, since such a system has a switching mechanism, it is necessary for operating portions to be manufactured with high accuracy. This makes it difficult to miniaturize a camera system and also makes it difficult to reduce the manufacturing cost.
A system for generating an image by using visible-light signals and near-infrared-light signals regardless of whether the amount of incident light is large or small, without use of an IR cut filter, has also been proposed (e.g., refer to Japanese Unexamined Patent Application Publication No. 06-169461). This system, however, exhibits a deterioration of color reproduction.
In addition, a solid-state image capture element having a function for independently outputting visible-light signals and near-infrared-light signals has also been proposed (e.g., refer to Japanese Unexamined Patent Application Publication Nos. 2002-142228 and 2006-190958). The use of the solid-state image capture element can obtain a color image with favorable color reproduction without use of an IR cut filter. Also, use of near-infrared-light signals when the amount of incident light is small, like at night, makes it possible to obtain a brighter image.
The solid-state image capture element disclosed in Japanese Unexamined Patent Application Publication No. 2002-142228 employs a two-dimensionally arranged pixel array having four types of spectral characteristic. The disclosed solid-state image capture element, therefore, involves strictly defining spectra of color filters, arranged on the two-dimensionally arranged pixel array, in order to independently obtain visible-light signals and near-infrared-light signals. The solid-state image capture element also involves performing matrix computation processing, which is difficult to achieve.
In the solid-state image capture elements disclosed in Japanese Unexamined Patent Application Publication Nos. 2002-142228 and 2006-190958, in order to obtain both visible-light signals and near-infrared-light signals, pixels having sensitivity to near infrared light are arranged in addition to pixels having sensitivity to visible light. The arrangement involves a change in a typical color filter arrangement, such as a Bayer arrangement, for the solid-state image capture elements, and the luminance and color resolution of an image become insufficient.